Administration of the MapR-DB is done primarily via the commmand line (maprcli) or with the MapR Control System (MCS).
Regardless of whether the MapR-DB table is used for binary files or JSON documents, the same types of commands are used
with slightly different parameter options. MapR-DB administration is associated with tables, columns and column families,
and table regions.

The maximum number of map task slots to run simultaneously. The default
value of -1 specifies that the number of map task slots is based on the total amount
of memory reserved for MapReduce by the Warden. For more information, see Resource Allocation for Jobs and Applications.

Default value: -1

mapreduce.tasktracker.prefetch.maptasks

The proportion of map tasks that can be scheduled in advance (prefetched)
on a TaskTracker. The number is given as a ratio of prefetched tasks to the
total number of map slots. For example, 0.25 means the number of prefetched
tasks = 25% of the total number of map slots. The default is 0.0, which
means no prefetched tasks can be scheduled.

Default value: 0.0

mapreduce.tasktracker.reserved.physicalmemory.mb.low

This property's value sets the target memory usage level when the
TaskTracker kills tasks to reduce total memory usage. This property's value
represents a percentage of the amount in the
mapreduce.tasktracker.reserved.physicalmemory.mb value.

Default value: 0.8

mapreduce.tasktracker.task.slowlaunch

Set this property's value to True to wait after each task launch for nodes
running critical services like CLDB, JobTracker, and ZooKeeper.

Default value: False

mapreduce.tasktracker.volume.healthcheck.interval

This property's value defines the frequency in milliseconds that the
TaskTracker checks the Mapreduce volume defined in the
${mapr.localvolumes.path}/mapred/ property.

Default value: 60000

mapreduce.use.maprfs

Use MapR-FS for shuffle and sort/merge.

Default value: True

mapred.userlog.retain.hours

This property's value specifies the maximum time, in hours, to retain the
user-logs after job completion.

Default value: 24

mapred.userlog.retain.hours.max

This property's value specifies the highest legal value for the
mapred.userlog.retain.hours property. When a user specifies a
value for mapred.userlog.retain.hours in excess of the value of
the mapred.userlog.retain.hours.max property, that value is
ignored and the value of the mapred.userlog.retain.hours.max
property is used instead.

Default value: 168

mapred.user.jobconf.limit

The maximum allowed size of the user jobconf. The default is set to 5
MB.

Default value: 5242880

mapred.userlog.limit.kb

Deprecated: The maximum size of user-logs of each task in KB. 0 disables
the cap.

Default value: 0

mapreduce.use.fastreduce

Expert: Merge map outputs without copying.

Default value: False

mapred.tasktracker.reduce.tasks.maximum

The maximum number of reduce task slots to run simultaneously. The
default value of -1 specifies that the number of reduce task slots is based on the
total amount of memory reserved for MapReduce by the Warden. For
more information, see Resource Allocation for Jobs and Applications.

Default value: -1

mapred.tasktracker.ephemeral.tasks.maximum

Reserved slot for small job scheduling

Default value: 1

mapred.tasktracker.ephemeral.tasks.timeout

Maximum time in milliseconds a task is allowed to occupy ephemeral slot

Default value: 10000

mapred.tasktracker.ephemeral.tasks.ulimit

Ulimit (bytes) on all tasks scheduled on an ephemeral slot

Default value: 4294967296

mapreduce.tasktracker.reserved.physicalmemory.mb

Maximum phyiscal memory TaskTracker should reserve for mapreduce
tasks. If tasks use more than the limit, task using maximum memory
will be killed. Expert only: Set this value only if TaskTracker should
use a certain amount of memory for mapreduce tasks. In MapR Distro
warden figures this number based on services configured on a
node. Setting mapreduce.tasktracker.reserved.physicalmemory.mb to -1
will disable physical memory accounting and task management.

mapred.tasktracker.expiry.interval

Expert: This property's value specifies a time interval in milliseconds.
After this interval expires without any heartbeats sent, a TaskTracker is
marked lost.

Default value: 600000

mapreduce.tasktracker.heapbased.memory.management

Expert only: If the admin wants to prevent swapping by not launching too
many tasks, use this option. Task's memory usage is based on max java
heap size (-Xmx). By default, -Xmx will be computed by the TaskTracker
based on slots and memory reserved for mapreduce tasks. See
mapred.map.child.java.opts/mapred.reduce.child.java.opts.

Default value: false

mapreduce.tasktracker.jvm.idle.time

If JVM is idle for more than mapreduce.tasktracker.jvm.idle.time
(milliseconds) TaskTracker will kill it.

Default value: 10000

mapred.max.tracker.failures

The number of task failures on a TaskTracker of a given job after which new
tasks of that job aren't assigned to it.

Default value: 4

mapred.max.tracker.blacklists

The number of blacklists for a TaskTracker by various jobs after which the
TaskTracker could be blacklisted across all jobs. The TaskTracker will be
given tasks later (after a day). The TaskTracker will become healthy after a
restart.

Default value: 4

mapred.task.tracker.http.address

This property's value specifies the HTTP server address and port for the
TaskTracker. Specify 0 as the port to make the server start on a free
port.

Default value: 0.0.0.0:50060

mapred.task.tracker.report.address

The IP address and port that TaskTrackeer server listens on. Since it is
only connected to by the tasks, it uses the local interface. EXPERT ONLY.
Only change this value if your host does not have a loopback interface.

Default value: 127.0.0.1:0

mapreduce.tasktracker.group

Expert: Group to which TaskTracker belongs. If LinuxTaskController is
configured via the mapreduce.tasktracker.taskcontroller value,
the group owner of the task-controller binary
$HADOOP_HOME/bin/platform/bin/task-controller must be same as
this group.

Default value: mapr

mapred.tasktracker.task-controller.config.overwrite

The LinuxTaskController needs a configuration file set at
$HADOOP_HOME/conf/taskcontroller.cfg. The
configuration file takes the following parameters:

mapred.local.dir = Local dir used by TaskTracker, taken from
mapred-site.xml.

hadoop.log.dir = hadoop log dir, taken from system properties of the
TaskTracker process

mapreduce.tasktracker.group = groups allowed to run TaskTracker see
'mapreduce.tasktracker.group'

min.user.id = Don't allow any user below
this uid to launch a task.

banned.users = Users who are not allowed to launch
any tasks.

If set to true, TaskTracker will always overwrite config file with
default values as

min.user.id = -1(check disabled), banned.users = bin,
mapreduce.tasktracker.group = root To disable this configuration and
use a custom configuration, set this property's value to False and restart
the TaskTracker.

Default value: true

mapred.tasktracker.indexcache.mb

This property's value specifies the maximum amount of memory allocated by
the TaskTracker for the index cache. The index cache is used when the
TaskTracker serves map outputs to reducers.

Default value: 10

mapred.tasktracker.instrumentation

Expert: The instrumentation class to associate with each TaskTracker.

Default value:
org.apache.hadoop.mapred.TaskTrackerMetricsInst

mapred.task.tracker.task-controller

This property's value specifies the TaskController that launches and
manages task execution.

Default value:
org.apache.hadoop.mapred.LinuxTaskController

mapred.tasktracker.taskmemorymanager.killtask.maxRSS

Set this property's value to True to kill tasks that are using maximum
memory when the total number of MapReduce tasks exceeds the limit specified
in the TaskTracker's
mapreduce.tasktracker.reserved.physicalmemory.mb property.
Tasks are killed in most-recently-launched order.

Default value: False

mapred.tasktracker.taskmemorymanager.monitoring-interval

This property's value specifies an interval in milliseconds that
TaskTracker waits between monitoring the memory usage of tasks. This
property is only used when tasks memory management is enabled by setting the
property mapred.tasktracker.tasks.maxmemory to True.

Default value: 3000

mapred.tasktracker.tasks.sleeptime-before-sigkill

This property's value sets the time in milliseconds that the TaskTracker
waits before sending a SIGKILL to a process after it has been sent a
SIGTERM.

Default value: 5000

mapred.temp.dir

A shared directory for temporary files.

Default value: ${hadoop.tmp.dir}/mapred/temp

mapreduce.cluster.map.userlog.retain-size

This property's value specifies the number of bytes to retain from map task
logs. The default value of -1 disables this feature.

mapreduce.cluster.reduce.userlog.retain-size

This property's value specifies the number of bytes to retain from reduce
task logs. The default value of -1 disables this feature.

mapreduce.heartbeat.10000

This property's value specifies a heartbeat time in milliseconds for a
medium cluster of 1001 to 10000 nodes. Scales linearly between 10s -
100s.

Default value: 100000

mapreduce.heartbeat.1000

This property's value specifies a heartbeat time in milliseconds for a
medium cluster of 101 to 1000 nodes. Scales linearly between 1s - 10s.

Default value: 10000

mapreduce.heartbeat.100

This property's value specifies a heartbeat time in milliseconds for a
medium cluster of 11 to 100 nodes. Scales linearly between 300ms - 1s.

Default value: 1000

mapreduce.heartbeat.10

This property's value specifies a heartbeat time in milliseconds for a
medium cluster of 1 to 10 nodes.

Default value: 300

mapreduce.job.complete.cancel.delegation.tokens

Set this property's value to False to prevent unregister or cancel
delegation tokens from renewing.

Default value: True

mapreduce.jobtracker.inline.setup.cleanup

Set this property's value to True to make the JobTracker attempt to set up
and clean up the job by itself or do it in setup/cleanup task.